How to match material properties to physical reality?
Here's a wonderful tutorial by Blender Guru for making a completely accurate metallic shader. I would follow his tutorial, and use this list of colors to set up your gold. Metal in real life has different colors on the edges facing away from you than the ones facing you, so this tutorial and data-table should describe how to set it all up. This approach may also be simpler than trying to interpret the graphs and curves you are currently having problems with. It's kind of a workaround, but I hope it helps! Cheers, 
Graves Broderick